A groundwater production well (also sometimes referred to herein as a “groundwater well”, a “production well”, or simply as a “well”) is a structure where groundwater is produced for consumption by people, animal livestock, agricultural purposes as well as industrial purposes (such as refining, mining, landfills, technology and so forth). Groundwater production wells can also include test holes for groundwater exploration. These wells consist of a support casing and well screen—through which groundwater enters the well. These wells may also be constructed in bedrock and serve the same purpose. There is also a primary pump inside the well, typically consisting of a line shaft turbine or electric submersible pump that is positioned at depth inside the well. The depth set location of the pump is derived from many factors that come into play such as 1) depth to water, 2) pumping water level, 3) rate of declining water table, 4) rate of recharge to the aquifer, 5) the depth of the target zones to be pumped on by the primary pump, and 6) the storage and transmissivity of the aquifer itself. Typically, the pump diameters are large relative to the size of the support casing and well screen as well as the pump column that extends between the pump and the ground surface. Moreover, each section of pump column is connected by means of a larger diameter threaded collar. Therefore, the pump column consists of ten to twenty foot sections of pipe of a smaller diameter but terminated on each end by a collar that is at least one-half inch to one inch larger than the main section of the pipe itself.
Global warming combined with increasing population has placed a larger demand on groundwater resources worldwide. As such, existing primary pumps in municipal, agricultural and industrial wells with long vertical and segmented sections of perforations, are periodically lowered to deeper pump intake locations inside the well as water tables around the world continue to deepen due to over-pumping of groundwater supplies combined with protracted drought. If the water level inside the well drops too much, the pump begins to cavitate (sucking in a combination of air and water). Therefore, it can be desired to lower the pump to a more favorable depth location in order to prevent production disruptions.
Conventional flow, chemistry and other types of sensor based down-hole measurement technologies, as well as down-hole groundwater sampling technologies that are used to collect samples for analysis and field based chemical analysis, are most often too large to collect this data within the annulus between the primary pump and the support casing and/or the well screen. Thus, the primary pump typically needs to be removed before any such technologies can be moved into the well.
Additionally, in situations where the well is not straight as it extends downward, existing conventional technologies require modifications in order to be centered inside the production well along the central axis. Then, a standard correction factor must be applied to convert the centralized measurements to an estimate of the average bulk flow rate—essentially a statistical extrapolation for measuring the cumulative flow through the cross-sectional area of the well (through any depth-defined imaginary horizontal plane that is perpendicular to the length of the well). Therefore, placement of the conventional technologies requires first removing the existing pump assembly from the well so that they can be inserted into the wells; with large protruding centralizers surrounding the tool. The centralizers keep the tool centered through the well during the entire profiling survey.
While some currently available systems do include water samplers and/or flow detection technologies that can be small enough to pass the pump through the annular space in many instances, such technologies still require multiple trips into and out of the well to obtain the water samples and corresponding flow rates at the desired depths. For example, for each water sample collected, the water sampler must be removed from the well for sample retrieval, then decontaminated at the ground surface, and then followed by reinstallation back into the well and lowered to the next sampling depth. Each time the water sampler is lowered into the well, the mechanical or optical counter that is used must be reset in order to track the vertical descent distance to the next sampling location. As the water sampler moves into and out of the well, water, oil, bio-slime, rust slime and so forth build up on the outside of the water sampler, causing the water sampler to slip over the roller of the various types of counters. In doing so, sampling depth errors may then occur which can create offsets and errors in the data. Some of the errors can be significant and can misdirect the science team and others involved in the decision-making process as to where contaminants are entering the well. Such misdirected decisions may then lead to incorrectly applied rehabilitation procedures, such as setting of inflatable packers and expandable sleeves at the wrong depth, thereby blocking good water from coming into the well as opposed to the bad water quality the producer is trying to avoid. Moreover, there is risk and legal liabilities associated with misplacement of packers, sleeves, engineered suctions and pump depths since incorrect placement of these well modifying structures can be costly and time-consuming. These types of errors can lead to contract disputes, liquidated damages, ill will and loss of reputation for the service providers who profile and modify these wells.
Further, current systems further require additional trip(s) into and out of the well for purposes of detecting flow of the water within the well at any desired depths. For example, in current systems, multiple trips into the well are required with the multiple trips including at least once for the flow detection technologies, and then followed by multiple times for a single tube bailer to sample multiple depths.
Additionally, in recent years, various technologies have been previously employed for purposes of detecting flow of the groundwater within the groundwater production well. Unfortunately, such technologies all have experienced certain limitations when it comes to accurately detecting the ambient flow (i.e. the non-pumping flow) of the groundwater within the well. For example, most conventional devices for purposes of detecting the ambient flow of the groundwater within the well are simply too large to easily fit down into the well with the pump assembly positioned therein. Additionally, such conventional devices also require multiple trips into and out of the well, as water sampling and flow detection are typically conducted separately and at only a single depth per trip. As noted above, such issues can lead to problems in terms of accuracy, as well as causing time-related and cost-related problems. Moreover, due to the size of these components in existing systems, any thought of conjoining such technologies or integration of their electronics would also be problematic.
Thus, it is desired to develop water sampling assemblies that are configured to overcome the drawbacks experienced by currently available technologies.